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Coleoptera of Great Smoky Mountains National Park Species Pages

Family Staphylinidae

            Tribe Athetini

 Geostiba coeligena Gusarov

Geostiba sp. All species in GSMNP are essentially identical externally.

Description and Taxonomy

Length 1.8-1.9 mm. This genus belongs to the subfamily Aleocharinae, one of the poorest known and hardest to identify groups of beetles. Diagnostic characters of Geostiba and differences from related genera are discussed in detail in the recent revision of Gusarov (2002). This paper also provided multiple illustrations of numerous morphological details important in identification of the genus and its species, as well as a species identification key. For a more generalized naturalist, members of the genus Geostiba from the GSMNP may be identified as small (ca. 2 mm long), narrow, parallel-sided staphylinid beetles with strongly reduced eyes, absent wings and, correspondingly, very small elytra. They are found in forest litter at higher elevations, primarily in spruce and fir dominated forests. Fifteen species are known to inhabit North America, two in the west (one native and one introduced European species), in the east and north-east and in the southern Appalachians, where 11 species are known. Five species from this latter group are found in the GSMNP (Gusarov 2002). Identification of the species requires careful preparation of genitalia mounts. This page is based entirely on Gusarov's (2002) revision. Extensive material collected since 2001 is in the process of identification. Multiple new records of Geostiba species and discovery of new species is expected from the results of these identifications. 

Life History

All species of the genus are found in leaf litter of montane forests, mostly above 1500 m elevation. They are extremely rare below 1200 m (Gusarov 2002). Spruce and fir forests therefore are the prime habitat for Geostiba species. Also, they are found in highland deciduous forests (beech, birch, and buckeye) and in upper parts of hemlock forests.  In GSMNP adults of this species were found in June at 1930-1950 m altitude.  

Distribution

This species is an endemic of the Great Smoky Mountains known from two localities west of Clingmans Dome Mountain.

Conservation Concerns

Not under threat, but with such limited distribution at high elevations, could be prone to extinction from climate change or damage to habitat by atmospheric pollution.

Locality records in GSMNP.

Acknowledgements

Development of these pages was supported by grants from Discover Life in America and the National Science Foundation (DEB-0516311).

References

Gusarov, V.I. 2002. A revision of Nearctic species of the genus Geostiba Thomson, 1858 (Coleoptera: Staphylinidae: Aleocharinae). Zootaxa 81: 1-88.

 Posted 17 March 2007, A. K. Tishechkin, Louisiana State Arthropod Museum.

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